Seed Development And Protein Properties Of Kidney Bean

Kidney bean is a hardy legumes planted wide in cold and humid environment, where is cool and mountainous. China is the major country of producing kidney beans, and export volume increased year by year, export prices higher than other country, kidney bean has been China’s important agricultural exports. Kidney bean contain abundant nutritious,containing more protein, dietary fiber, trace elements, and low fat content than other crops,is a good resource as edible and medicinal plant. With the adjustment of health and nutrition awareness about diet enhanced, as a food protein resource, kidneybean has a rapid rise in modern functional food development. Therefore, strengthen the kidney bean variety breeding, cultivation and deep processing technology research and promotion, seed growth characteristics and explore the kidney bean protein properties, which have great significance for kidney bean resources utilization, industrial and agricultural production.This study take different kidney bean varieties as materials, by comparing the grain formation in the process of substance content changes,the nutrient value of the grain formation were evaluated. At the same time, based on the optimization of extraction of kidney bean protein method, the kidney bean protein physicochemical functional properties at different extraction conditions were determined. The main conclusions of the study are as follows:1. Based on four kidney bean, the matter content of determinationwas compared in the process of the seeds maturing, studies have shown that fat, soluble sugar, starch and ash in the different varieties of beans is not obvious, and these substances content of the same breed in different periods changed more obvious; fat content changed slightly elevated and reached a maximum at 25 d after flowering, an average of 1.65%, after decreased; soluble sugar content and ash content as a whole was gradually increasing trend; starch content changed due to different varieties showing not exactly the same trend, the overall amplitude was small.2. Crude protein content offour kidney beans in different ripening process changed in the same trend, showed a V-shaped, which gradually increased after the reduced, reached maximum when maturity. The proportion of water-soluble proteins during the formation was the largest in total protein, gliadin content minimum, plus a small amount ofnon-protein nitrogen. Beans grain maturation process whose essential amino acids representing the measured ratio of 30.74%~41.42%, accounting for the proportion of intake of essential amino acids(35%) and diet substantially held constant. Glutamate and proline content were higher in the grain maturation process.3. Moisture, ash, crude protein, crude fat and total sugar content of defatted and peeling kidney bean flour were 10.01g/100 g, 2.88g/100 g, 24.32g/100 g, 1.12 g /100 g,56.53g/100 g, described kidney beans is a high-protein and low-fat crops. Explored by single factor test p H, liquid ratio, extraction time and temperature on the extraction rate of kidney bean protein extraction, the application of the selection and Box-Behnken experimental level, the application of response surface analysis of the factors and optimal level range their interactions were analyzed to obtain optimum extraction conditions for p H 10.42,extraction time 1.57 h, 20 : 1 liquid ratio(m L/g), extraction temperature 40.61 ℃, the maximum theoretical value. under these conditions the rate of kidney bean extract to69.79%.4. The functional and physicochemical properties of kidney beans under different protein extraction conditions have determined, the results showed, with the extraction p H decreased after the increased, the protein purity increased. The kidney beans isoelectric point is 4.2, and in the vicinity of isoelectric point the protein solubility is lowest, this law is not impactedby electric extraction conditions; extraction of p H and temperature on the solubility of the protein mainly in the p H is too high and the extraction temperature is too high or too low, decreased solubility of proteins, protein extraction visible needs relatively mild conditions, otherwise it would reduce the solubility of protein denaturation, thereby affecting other functional properties. Kidney bean extract different proteins emulsifying under p H conditions have some differences, when the p H is 12 to extract the best emulsifying protein extraction p H of the emulsion stability 10:00 best.5. SDS-PAGE electrophoresis results showed that the main protein subunit of kidney beans was about 14 bands, subunit molecular mass rangedin 15.9-52.2k Da. The most obvious bands molecular weight was 47.4k Da, 44.3k Da, 32.5k Da, 26.0k Da, 19.0k Da.Extracted protein subunits of Kidney bean under different conditions were relatively small differences in the molecular weight distribution, and when protein extraction p H was 10 and11, there were a 23.8k Da subunits, the mechanism needs further study.